Currently, known in the art is a moisture sensor (DE patent No. 3829517, cl. G01N25/56, 1989) wherein on a surface of a flat substrate made of low heat conductivity material, a tape heater in the form of meander is printed, on which an insulation layer is sprayed and on which, in turn, a moisture sensitive layer is deposited with a sensitive element inside the latter.
The prior art moisture sensor operates on the principle of cyclic conversion of a moisture sensitive layer parameter proportional to moisture of the environment, to an electric signal to be measured at the sensitive element outputs when the sensor reaches the ambient temperature. After the measurement period is finished, voltage is fed to the heater located on the substrate and separated from the moisture-sensitive layer by an insulating layer due to which a temperature of the whole moisture sensor begins to rise to the preset value, and as a result, the moisture-sensitive layer is dried; then the heating is stopped and the sensor cools down naturally, whereupon the measurement cycle is repeated.
Thus, the prior art moisture sensor has a long relaxation time (response speed), inasmuch as the heater and moisture sensitive layer are separated, which slows down a reaction of the moisture sensitive layer to ambient parameter changes.
Moreover, the prior art moisture sensor has a low efficiency due to the presence of an insulating layer between the heater and moisture sensitive layer, which leads to additional power consumption because power of the heater is additionally consumed for the heating of the insulating layer and substrate.